Bus-bar structure



Oct. 28, 1924.

D. F. MINER BUS-BAR STRUCTURE Filed Sept. 24 1920 r l lll ll III Ill INVENTOR WITNESSES:

ATTORNEY Patented Oct. 28, 1924.

UNITED STATES,

pxrrirrr OFFICE.

DOUGLAS F. MINER, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION O'F PENNSYL- V'ANIA- BUS-BAR STRUCTURE.

Application fifled September 24, 1920. Serial No. 412,530.

To all whom it may concern:

Beitknown that I, DOUGLAS F. a citizen-of the United dent of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Bus-Bar Structures, of which the following 'is'a specification.

My invention relates to electrical conductors and particularly to parallel inductively related conductors such as bus-bars.

The object of my invention is to 'so modify the effects of mutual induction between a plurality of parallel conductors as to eliminate undue heating in the conductors and permit the same to be utilized more efi'ectively and economically.

Where both lines of an alternating-current circuit, such as in bus-bar structures, comprise composite conductors disposed adjacent to each other, there is a relatively great mutual inductive effect. .Theeffect upon the adjacent or inner component conductors of the composite conductors is to MINER, States, and a resi- 26 reduce the reactance thereof caused bythe neutralizing fields of the conductors 0;f'opposite polarity. Because of the decreased reactance, more current flows through the ad jacent conductors of the com osite conduc- 30 tors'than the others, with te result that they heat by greater amounts than the remaining component conductors. Also, the component conductors of the respective composite conductors decrease in" heating characteristics in proportion to the distance be tween them. Thus, feet ofthe fields of the composite conductors of opposite polarity decreases the reactance, the current increases and the most re- 40 mote component conductors carry less current and operate at the lowest temperatures. This prevents the utilization of all of the conductors at their maximum etficiency, because the value of the total current is limited by the temperature of the hottest conductor. Therefore, only one component bar of each composite conductor is utilized at' its maximum efiiciency while the others are carrying less current than their capacities warrant for a temperature 'rise equivalent to that of the hottest bar.

In practicing my invention, I place a magnetizable member or members between,

an in parallel relation to, parallel induc- 66 tively related conductors of'oppos'ite polarber with the conductor.

as the neutralizing efity to divert and separate the fluxlines of their respective fields and to thereby eliminate the neutralizing efiectthereof. Thus, a moreequal distribution of current between the conductors and a reduction in the heating characteristics of theadjacent component conductors of the composite conductors is efiected. By reason of the uniform distribution of current thus effected, the watt loss, which is in proportion to the square of the current in each conductor, is equalized. Thus, the total watt loss of the combined conductors is reduced in accordance with well known principles.

In my copending application, Serial N 0. 412,531, filed Sept. 24, 1920, is disclosed a structure for accomplishing results similar to those herein set forth by having the conductors of special forms and relations instead of byassociating a magnetizablemem- Other devices appertaining to the distribution of current in conductors are set forth in my copending applications, Serial No. 410,896, filed Sept. 24,1920, and Serial No. 412,529, filed Sept. 24, 1920, and in a copending application of C. F. Wagner, Serial No. 412,461, filed Sept.- 24, 1920, and'assigned to the Westinghouse Electric & Manufacturing Company.

Figure 1 of the accompanying drawings is a diagrammatic view, partially in elevation and partially in section, of a portion of a bus-bar structure embodying my'invention, as viewed in the direction of the bus-bars.

Figs. 2 and 3 are similar diagrammatic views showing'the magnetic fields of induc-- tively related bus-bars as usually employed and as employed in accordance with my in-' vention, respectively, and

Fig. 4 is a view, similar to Fig. 1, of a modified form of my invention.

In Fig. 1, two adjacent groups 1 and 2 of bus-bars 3 are mounted on insulators 4 and 5, respectively, and disposed in parallel relation with respect to each other. Each group constitutes a composite conductor employed as one conductor of an alternatingcurrent circuit.

The several bus-bars 3 9f each group may of the central leg H A magnetizable member 11, preferably constructed of laminated iron' or steel and of rectangular cross-sectional area, is supported intermediate the groups 1 and 2 in anysuitable manner, as by being secured to an insulator 12 by metallic members 13, and extends parallel to the bus-bars 3 substantially throughout the length of the latter.

The effect of the above arrangement is somewhat as illustrated in Fig. 3 where, for simplicity, single bus-bars are employed to represent the groups 1 and 2. This effect is to form a path of low reluctancebetween the respective groups in contra-distinction to the usual method of mounting bus-bars, illustrated in Fig. 2. In the latter form, some of the magnetic flux encircles both groups of conductors and distorts and partially neutralizes the field, causing a reduction of the reactance of the adjacent or inner bars '3 of the respective groups 1 and 2. These conductors, therefore carry more current than the others and consequently are heated to higher temperaturesthan the others. With the bus-bars and the magnetizable member 11 arranged in accordance with my invention, a low reluctance path is offered to the flux of each group of bus-bars so that very little flux encircles the two groups, and the field neutralizing effect is eliminated. By reason of this effect a better distribution of current is attained tending to equalize the heating and to render the whole structure more effective and economical in the manner previouslydefined.

In Fig. 4, in'which similar parts are designated by similar reference numerals, instead of the single magnetizable member 11, a pair of spaced parallel magnetizable members 14 are similarly related to the bus-bars.

This arrangement separates the magnetic fields of the respective groups of bus-bars by a greater distance. In fact, the number of the groups of bus-bars and magnetizable members and the proportions of copper and iron therein may be variously modified to obtain any desired distribution of the magnetic field in accordance with the existing con- I ditions.

fected by the flux fields of the group of opposite polarity, of a magnetic means disposed between the groups for localizing the flux field of the groups.

2. The combination with a plurality of inductively related groups of conductors of opposite polarity, each of which contains a plurality of separate conductors connected'in parallel and adapted to be individually effected by the flux fields of the group of opposite polarity, of a magnetizable bar disposed between the groups and extending substantially the full length of the conductors for reducing the inductive effects of the field of one group upon the conductors of the other group.

'3. In a bus-bar structure, the combination with a plurality of inductively related groups of bus-bars of opposite polarity, each of which comprises a plurality of spaced parallel extending bus-bars, of a magnetizable bar disposed between the groups for providing a low reluctance path between the groups tending to localize the fields thereof. r

4. In a bus-bar structure, the combination with a plurality of inductively related groups of bus-bars of opposite polarity, each of which comprises a plurality of spaced parallel extending bus-bars, of a pair of magnetiz: able bars spaced apart and disposed between the groups for providing low reluctance paths between the groups tending to localize the fields thereof.

In testimony whereof, I have hereunto subscribed my name this 17th day of September, 1920.

DOUGLAS F. MINER. 

